Until last year, I spent every day of my adult life (over 35 years) in dental offices.

One thing I know all about are dentifrices. I even know which brands took the longest to stop using the harsh abrasives.

I was one of those Dental Company lifers.

All of that useless info aside, Automotive rubbing and/or polishing compounds are probably the next best thing, assuming that you discovered you're out of the surprisingly cheap stuff called valve lapping compound, and also found that your car is out of gas, so you can't buzz over to the auto store, hardware store, or WalMart.

Most of the time, it's the buildup that needs to be removed from the valve and seats. More of a cleaning than a grinding. If it's been there too long, your car / bike, r/c motor is going to need more than paste.

Of course, there's always blw's revelation that nobody actually said that anyway, so nobody really wants to know.

"A waste of time" might be a fair assessment of this, except that I just got off the phone with the State of Texas. An hour and a half.

Makes one realize that "A waste of time" comes in many sizes, and Texas does everything extra big when it comes to red tape.

Until last year, I spent every day of my adult life (over 35 years) in dental offices.

One thing I know all about are dentifrices. I even know which brands took the longest to stop using the harsh abrasives.

I was one of those Dental Company lifers.

All of that useless info aside, Automotive rubbing and/or polishing compounds are probably the next best thing, assuming that you discovered you're out of the surprisingly cheap stuff called valve lapping compound, and also found that your car is out of gas, so you can't buzz over to the auto store, hardware store, or WalMart.

Most of the time, it's the buildup that needs to be removed from the valve and seats. More of a cleaning than a grinding. If it's been there too long, your car / bike, r/c motor is going to need more than paste.

~ Jim ~

I wouldn't want to use valve lapping/grinding compound on a Saito valve seat.

I haven't seen any buildup on any Saito seats I ever had. I had a couple of valves lock up during one winter when I forgot to use after-run oil late in the fall.

They weren't frozen, so much as sticky. I put after-run oil in and worked them for a while. I'm sure some scale had developed over the winter. Fortunately, no lasting effects.

Compared to auto and motorcycle heads, the Saitos I work on are always pristine in comparison. I suppose a lot depends upon the conditions under which it was run. Cowled in without a lot of air, running hot for that reason or some other reason. The glows can get buildup from heat, that's for sure.

I'm all but out of the Saito club these days. One .72a, in my little Sig Sundancer Bipe. Powerful for a small 4-stroke!

I've gone to gassers for the rest. But my flying buddies will see to it that I still get to work on plenty of them! Phil brought a radial over the other day to troubleshoot. Once we took that dust cover off the venturi, it ran pretty good!

Hey guys,
I was just spoken to pretty harshly by a Mod over some things I said in here. I've posted less than a half-dozen times in the last day or so, I don't remember insulting anybody, picking any fights, or saying anything derisive about RCU (???) but if anything I said was in any way amiss, I apologize, and did not realize I was being anything other than chatty and conversational.

G'day RJ,
I always prefer Stainless bearings, a lot less rust to worry about, & I know someone will disagree,
but with a 4 stroke, the revs are a lot less than a 2 stroke, so high performance is not an issue.
Just my 2 cents worth.

Rowdyjoe, ...I look at these factors ; 1 - how much am I going to use that engine
2 - what size model am I going to put it in
the econo bearings are ok, I have them in several engines, and at the other end of the scale, I dont believe there is anything gained from using the most expensive ones, so it really is a matter of choice
A.A. Barry

Ernie,
Wasn't aware of RC Bearings until now. Everyone recommends Boca so, that's where I bought mine.
Yes, the price does appear to be much cheaper at RC Bearings. Assuming the quality is the same, it's a deal you can't refuse ....about 1/2 price.

Well, I only have a couple of Saitos, but found them to be superior engines. Some many years ago when they first came out with the .30 with exposed rockers, I bought one and put it in a swizzle stick and used it as a trainer. I ran it on stock 10% fuel which had some castor in it. I ran it many many hours. Finally I fouind the valve stems so worn that they looked like they would break if you touched one. I had to buy a complete head which had the valves etc in it as a unit.
When I took the engine down, it was clean inside and when I reassembled it with the new head/valves the compression was as new...I could not find any wear in the sleeve or piston....don't know what they used but that baby had many hours of running and still was as tight as new....
They make one fine and long lasting engine....the best!!!! I have an 80 of theirs in a Bruce Tharp Flyin' King and it pulls it with authority....

Regards to all,
Frank Schwartz AMA123
87 years young and still building and flying...........happiness, for sure.....

You have to fit them carefully no matter what type of bearing you use. Ceramics are especially fussy when it come to installation. I like standard high performance steel bearings myself. I believe SS is softer than normal steels. Just my two cents.
John

Frank, we had a crazy club member who had a red Flying King and the 80 pulled it with stump pulling authority. I saw several dozen imminent crashes saved literally at the last second only by the sheer grunt power of the 80.

I also saw that this Flying King would fly perfectly fine with all of the covering peeled back from the whole fuselage side. Flapping back in the breeze like a streamer. Flight after flight.

I ordered a gasket kit and a few other small items from Advantage Hobby. They had everything I needed at a better price than Horizon and they are Saito parts ...not after-market. I've called my experienced friend who has rebuilt many, many glow engines and he agreed to help me with my FA-80GK. We'll do the deed as soon as the parts arrive.

OOOPs ....almost forgot to mention the results of the carb kit installation. The engine is running much better now but, still haven't found the sweet spot. Ihaven't been able to get the idle below 2400 and the max rpm is around 9100 with a 13x6 prop. However, it's not running a steady rpm at full throttle. It will vary by as much as 200 to 300 rpm when peaked. Before installing the kit, I saw as much as 10k rpm at full throttle with the same size prop.
Any ideas or opinions on what may be causing this variation at full throttle?
I'm getting a good transition now where I couldn't get one at all before. I need to get the low end and high end tuned now.

Stainless is harder but, more brittle than other steel alloys. I went with stainless to reduce the chance of corrosion.

JNorton was right. SS is softer than carbon steel, but it is tougher. It resists corrosion & in rifle barrels, it also resists errosion in the throat from hot gasses. It can also be harder to machine.

High carbon steel is harder & more brittle than SS. I much prefer high carbon steel to SS if knife blades. SS is harder to get a good edge on & it doesn't stay sharp as long . When corrosion is an issue, like razor blades, SS cutting edges last longer.

Hello all, I’m new to forum. However, I've read a ton of posts before becoming a member and there seems to be a constant request for test results. This is what I've got so far on My Saito 100.
A little history first, I started as a glow guy then left the hobby for several years before getting back into it because the advances in battery and brushless motors intrigued me. Then I heard that sweet sound of a four stroke glow motor. I'm never going back to electric or 2 stroke. Ok, Here are my results:

NOTE 1: In both cases i ran the props before and after balancing and in both cases I had close to a 150 rpm increase.
NOTE 2: The lower idle in the second setup is mostly due to the onboard glow driver but the 30% fuel also helps.
NOTE 3: I haven’t done any tests yet on the biggest cause of increase in RPM on the top but I bet its half fuel and half after market muffler.
NOTE 4: This engine runs very cool when using 30%N Fuel
LAST NOTE: I have learned so much from so many in this forum. Thanks for sharing.